Solid-Lattice Hip Prosthesis Design: Applying Topology and Lattice Optimization to Reduce Stress Shielding from Hip Implants

The goal of this study was to construct a methodology and process for designing a prosthesis which would reduce stress shielding and meet standard fatigue life requirements. Stress shielding is the reduction of bone stresses due to the introduction of an implant, which may lead to bone density decrease. Implants may become loose when stress shielding is present because bone resorption occurs as the bone adapts to the reduction of stresses in the bone.

For this study, a hip prosthesis was analyzed. Both topology and lattice optimization were performed using OptiStruct 14.0 where stress shielding and prosthesis fatigue strength were considered. The final optimized design reduced stress shielding by more than 50% when compared to a conventional generic implant, and the fatigue life met the ISO standard requirements. Additionally, manufacturability was considered in the design process and the final design can be produced by selective laser sintering of Ti-6Al-4V.